The present invention relates to an optical pickup apparatus used for recording and reproduction of an optical recording disk such as a compact disk (CD), a digital video (or versatile) disk (DVD), or the like, as well as a method of manufacturing the same. More particularly, the present invention concerns a technique for positioning a deflector mounted in an optical pickup apparatus.
As an optical pickup apparatus used for recording and reproduction of an optical recording disk such as a CD or a DVD, one is known in which laser light emitted from a laser diode is deflected by a half mirror, this laser light is built up by being deflected by a total reflection mirror, and this laser light is focused onto the optical recording disk in the form of a spot by an objective lens. The reflected light from the optical recording disk returns to the objective lens and is deflected by the total reflection mirror, and after being transmitted through the half mirror, the return light is focused onto a photodetector by a sensor lens. In the photodetector, a focusing error signal is generated on the basis of the configuration of the spot of the focused laser light, and a tracking error signal is generated by the intensity distribution of the spot.
In the optical pickup apparatus thus configured, when the total reflection mirror is mounted on an apparatus frame, the inclination angle of the total reflection mirror is adjusted to adjust the angle at which the laser light is made incident upon the objective lens, thereby suppressing the generation of coma by means of the objective lens.
With the optical pickup apparatus exclusively used for reproduction, it is not necessarily essential that the center of the spot and the center of the intensity distribution are aligned with each other, there are many cases where the center of the intensity distribution of the laser light emitted from the laser diode is offset from the optical axis of the laser light. In this case, the mere adjustment of the angle at which the laser light is made incident upon the objective lens does not bring the center of the intensity distribution of the laser light into alignment with the center of the spot formed by the objective lens.
Accordingly, if the optical pickup apparatus which also effects the recording on the optical recording disk is configured after the fashion of the optical pickup apparatus exclusively used for reproduction, there is a problem in that the quality of the spot is poor and high-quality recording cannot be effected due to the fact that the center of the spot of the laser light focused on the optical recording disk is offset from the center of the intensity distribution. In addition, if the center of the intensity distribution is offset from the center of the spot of the laser light focused on the optical recording disk, offset occurs in the tracking error signal generated by the photodetector when another optical recording disk is used. There is the problem that high-quality recording cannot be effected for this reason as well.
Accordingly, the object of the invention is to provide an optical pickup apparatus which is capable of high-quality recording as well as a method of manufacturing the same.
According to an aspect of the present invention, there is provided an optical pickup apparatus comprising:
a laser light emitting device;
a lens driver for moving an objective lens for conversing the laser light deflected by the deflector onto an optical recording disk in a focusing direction and a tracking direction thereof; and
a frame member for supporting the laser light emitting device and the lens driver,
wherein the optical axis of the objective lens is aligned with the center of the intensity distribution of the laser light.
According to another aspect of the present invention, there is provided a manufacturing method of an opticall pick up apparatus including: a laser light emitting device, a lens driver for moving an objective lens for conversing the laser light deflected by the deflector onto an optical recording disk in a focusing direction and a tracking direction thereof and a frame member for supporting the laser light emitting device and the lens driver, wherein the optical axis of the objective lens is aligned with the center of the intensity distribution of the laser light, the optical pick up prepared by a process comprising the steps of:
adjusting at least one of the laser emitting device and the objective lens in such a manner that the optical axis of the objective lens is aligned with the center of the intensity distribution of the laser light.